Hydraulic pump and valve



P. F. ROSSMANN 2,245,227

HYDRAULIC PUMP AND VALVE June 10, 1941.

F1193 Dec. 15; 1957 3'Skets-Sheet 1 64 I FIGB.

L J a J Q U INVENTOR DETEIQ F. Dossmnnu.

" ATTORNEY June 10, 1941. P. F. ROSSMANN HYDRAULIC PUMP AND VALVE FiledDec. 15, 1937 3 Sheets-Sheet 2 3! I III I II l 1 .2; I

INVENTOR PETER Ross/1mm.

ATTORNE v June 10, 194 1. p F' RQSSMANN 2,245,227

HYDRAULIC PUMP AND VALVE Filed Dec. 15, 1937 3 Sheets-Sheet 3 Hill | mgggggg-ngggugn j Sf EIIIIIIIIHi 7 7 X 1 I 6% INVENTOR ATTORNEY PatentedJune 10, 1941 HYDRAULIC rum AND VALVE Peter F. Rossmann, Kenmore, N. Y.,assignor to Curtiss Wright Corporation, a corporation of DelawareApplication December 15, 1937, Serial No. 179,884

3 Claims.

This invention relates to hydraulic systems and particularly, comprisesimprovements in hydraulic pump and valve mechanisms of the type adaptedfor use in the control of aircraft accessories.

Many modern aircraft are equipped with retractable landing gears andother adjustable devices which .must be controlled remotely by theaircraft crew. Hydraulic mechanisms are particularly suitable for thesecontrol functions and it is essential, under the design conditionsimposed, that the system'be capable of maintaining hydraulic pressuresof the order 'of 1,000 lbs/ sq. in. while holding the apparatus involvedto a minimum of weight.

The present invention is concerned with a hydraulic hand pump of thereciprocating type which may be manually operated, this pump beingconnected With a unitary valve system by which the fluid delivered bythe pump may be switched from one to another conduit connected with ahydraulic motor, whereby the operation of the hydraulic motor may bereversed. Concurrently, the unitary valve mechanism is adapted to switchthe conduits of the hydraulic motor for connection to the pump intakeObjectives of the invention are to provide a pump and valve organizationof great simplicity, combined with minimum weight and a maximum pressurecapacity.

A further object is to provide a manually oper- I able pump of thereciprocating type capable of fluid delivery at high pressure.

A further object is to provide a'unitary valve mechanism by which fluidflow may be reversed whereby the pump delivery and pump intake may beswitched between a pair of hydraulic motor conduits.

Further objects will become apparent in reading the annexed detaildescription in connection with the drawings in which Fig. 1 is anelevation, partly in section, of a hydraulic system according to theinvention,

showing the valves adjusted for retraction of a Fig. 9 is a section onthe line 9-9 of- Fig. 7;

Fig. 10 is a section on the line ll0 of Fig. 7, and

Fig. 11 is a fragmentary view of part of the valve assembly. 1

Referring to Figs. 1 and 2, I show a hydraulic reciprocating pump Ithaving an intake duct l connected to the middle thereof and a pressureduct it connected to an end thereof. The pressure duct connects with avalve cylinder [8, being one of four substantially similar valvecylinders I7, I8 19 and 20 joined together and comprising a unitaryvalve assembly 2|. As shown, the valve cylinder 20 is connected by aconduit 22 to a fluid reservoir 23 in turn, connected to the pump intakeconduit 15.

Referring now to Figs. 3 to 6 inclusive, the pump unit It is shown indetail, this comprising a cylinder 25 having similar end plugs 26retained by split-rings 21 engaging grooves in the cylinder ends. Theplugs 26 carry opposed pressure packings 28 to seal the cylinder againstleakage, and likewise, are provided with a ball check valve permittingoutflow of fluid from the cylinder and preventing inflow. The wall ofthe cylinder 25 is drilled as at 30 to communicate with the deliveryside of the valves 29, the drillings 30 being interconnected by a tube3|. One of the plugs 26 is provided with an outlet opening 32 to whichthe delivery conduit l6 may be attached. Intermediate the length of thecylinder is a transverse opening 34 adjacent which is mounted a boss 35having a large ball socket within which is engaged a ball 36 carrying anoutwardly extending operating handle 3! and an inwardly extendingprojection 38 having a parti-cylindrical end. The projection 38 engagesin a recess 38 formed in'an opposed piston unit 40 having piston heads4| facing respective plugs 26, the piston unit 40 incorporating checkvalves 42 and conduits #33 permitting fluid passage from the mid-portionof the cylinder 25 into the chambers defined between respective sets ofpiston heads 4| and plugs 2 The piston heads are packed as at 45 toprevent fluid leakage. As shown in Fig. 5, an opening 46 is providedthrough the boss 35 and the cylinder 25, this being connected to theintake conduit l5.

In operation, fluid enters the pump through the opening 46 and uponoscillation of the handle 31, fluid flows alternately through the checkvalves 42 and upon reverse oscillation of the handle the fluid confinedbetween the respective sets of piston heads 4| and plugs 26 is deliveredpast the check valves 29 into the delivery conduit so that in efiect, adouble acting pump is provided,

delivery from which is independent of the length of the oscillatingstroke of the handle 31. The leverage afforded by the length of thehandle'3l makes the pump capable of delivering fluid at very highpressure without undue effort by the operator.

In Figs. 1 and 2, I show a hydraulic motor 50 comprising apiston-cylinder combination having conduits i and 52. When fluidpressure is imposed through the conduit 52 retraction of the motor willbe effected as shown in Fig. 1, while, if fluid pressure is imposedthrough the conduit 5! extension of the motor will be caused as shown inFi 2.

The respective valve cylinders I! to 20 inclusive are substantiallysimilar in construction and each includes an intermediate valve seat 54with wh ch a poppet type valve 55 is engageable. A stem 56 of eachpoppet valve extends above the respective cylinder and is packed withrespect to the cylinder end by a packing 51. The valve is urged toward aclosing position by means of a spring 58 hearing on the valve bottom andabutting against a plug 59, packed as at 60 and retained in the cylinderby a split ring 6| engaging a groove formed in the cylinder. The severalcylinders l'l to 20 inclusive are mounted in in-line arrangement upon abracket 62, said bracket being extended at its ends to provide bearings63 for a camshaft 64 having cams 65, 66, 61, and 68 engageable with thestems of the valves in the respective cylinders l1, l8, l9,'and 20. Thecamshaft may be turned by means of a handle at an end thereof. Cylindersl1 and I6, and I9 and 20 are placed in communication by tubes 1| locatedbelow the valve seats 54. Cylinders l1 and 20, and I8 and I9, are placedin communication by tubes I2 and I3 entering respective cylinders abovethe valve seats 54. The pressure conduit l6 from the pump enters a sideopening 14 in the cylinder 18, above its valve-seat. The conduit 22connects with the cylinder 20 above the valve seat through an opening15. The conduits 5| and 52 enter the plugs 59 of the valve cylinders l1and I9, below respective valve seats. The cams 65 and 61, operating onthe valve cylinders l1 and I9, depress respective valve stems at thesame time, while the cams 66 and 68 are angularly offset from the cams65 and 61 and also are arranged to depress their coacting valve stems atthe same time. In other words, the valves of cylinders l1 and I!) willbe opened while the valves of cylinders I8 and 20 are closed andvice-versa. The functioning of the valve system in connection with thepump will be apparent from Figs. 1 and 2. In Fig. 1, the cam,- shaft 64has been turned to open the valves of cylinders l1 and I9 while thevalves of cylinders l8 and 20 are closed. Pressure fluid enters thevalve cylinder 18 above the closed valve and passes to valve cylinder l9through the tube 13,

whence it passesthe valve to enter the conduit 52 to effect retractionof the hydraulic motor 50.

Fluid from the left side of the motor piston con-,

currently flows through the conduit 5i into the valve cylinder Il, whosevalve is opened whereby the fluid flows on through the tube 12 to passthrough. the tube 22 to the reservoir 23, and thence, through theconduit I5 to the pump intake. In Fig. 2, when the camshaft is adjustedfor opening of the valves in the cylinders l8 and 20, pressure fluidpasses through the valve of cylinder I8 through the tube I I and intothe conduit 5| to effect extension of the motor 50. Fluid from the rightside of the piston of the motor passes through the tube 52 into thevalve cylinder l9, through the tube 1 I, through the valve of thecylinder 20 and thence, into the conduit 22 and to the pump aspreviously explained.

It will be apparent that a plurality of valve assemblies 2] and motorsmay be connected to a single pump l4 so that delivery from the pump maybe selectively adjusted by any one of the several valve assemblies.Camshafts on the respective assemblies may be adjusted to a neutralposition as indicated in Fig. 10 whereby fluid flow is prevented,neutralizing action of the hydraulic motor connected with the assembly.

While I have described my invention in detail in its present preferredembodiment, it will be obvious to those skilled in the art, afterunderstanding my invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Iaim in the appended claims to cover all such modifications and changes.

What I claim is:

1. In a hydraulic pump unit comprising 9. cylinder having a pistonreciprocable therein, the cylinder bore including similarly formed endseach having an annular shoulder toward the end and an annular groovebetween the shoulder and the end, a pump exit connection plugrotationally free in the bore and having an annular groove, the landsbordering the groove respectively engaging the cylinder bore and theannular shoulder, a snap ring engaging the cylinder groove locatingsaid, plug against axial displacement, opposed toroidal packings in saidplug groove sealing against leakage between the plug and cylinder, saidplug having an axial drilling and radial drillings communicatingtherewith, the radial drillings opening to the plug groove between saidpackings, and a conduit secured at its ends to the cylinder ends andopening to respective plug grooves.

2. In a reciprocable force pump, an open-ended cylinder having a pistontherein, closures for the cylinder ends comprising female screwconnections for receiving a pipe terminal, annular packings on saidclosures engaging the cylinder bore and allowing of relative rotation oftheclosures and cylinder, and means to hold said closures against axialmovement, the rotational freedom of-said closures permitting easyassembly of pipe engaged withthe cylinder groove to hold the plugagainst axial displacement.

PE'I'ER F. ROSSMANN.

